P.499 left column:"[Investigators'] prime objective in this work was to correlate the pattern of TUNEL [the method of TdT-mediated dUTP-biotin nick end labeling, see Method section in BNID 112334] staining in situ with data about systems in which PCD [programmed cell death] existence was already suspected through other means. The small intestine epithelium is typified by a high turnover rate (3-4 d for the replacement of the entire epithelium)
and well-defined architecture of repetitive proliferating units where the location of cells which are about to be disposed, is known through pulse-chase experiments (summarized
by primary source)."